SU1211765A1 - Device for differentiating envelope - Google Patents

Description

one

The invention relates to a computational test and can be used in control systems for generating a control signal.

The aim of the invention is to improve noise immunity.

The drawing shows a functional diagram of the device.

The device contains a block 1 sample storage, blocks subtraction 2 and 3 ,; smoothing filter 4, pulse generator 5, integrators 6 and 7, pulse distributor 8.

The device works as follows.

An amplitude-modulated alternating voltage is supplied to the input, which is integrated by integrators 6 and 7 periodically with a shift by half a cycle. At the end of each clock cycle, the integrators 6 and 7 are alternately zeroed. The duration of the integration interval is equal to the carrier period. The voltage at the output of subtraction unit 3 is proportional to the smoothed envelope value. Sample storage unit 1 samples the signal from the output of subtractor 3 at times when the control input receives voltage from the pulse distributor 8. This control voltage has the form of short duration pulses. The frequency of these pulses is generally a multiple of the carrier frequency and is selected depending on the required speed and device transmission coefficient — it can be equal to twice the carrier frequency, equal to it or an integer number of times less. In particular,

to

eleven

five

765

The information in block 1 can be updated by a pulse immediately before resetting each of the integrators -.

In this case, the output voltage of the sampling-storage unit 1 is equal in shape and size to the output voltage of the second adder 3 and is shifted relative to it by the time ut

t

If

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- i ftbie-

where f

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reference voltage frequency;

 - discharge time of the capacitors of integrators 6 and 7; VOL the sampling time of the voltage of the sampling-storage unit 1; L - time between the beginning of the discharge of the capacity of the integrators 6 or 7 and the end of the sampling voltage lc is zero if the discharge control is carried out by the falling edge of the sampling control pulse.

The voltage at the output of subtraction unit 2 is proportional to the first derivative of the envelope. Voltage drops are eliminated with the help of a smoothing filter 4. Instead of a filter, you can also use the second sampling-memory unit, which is controlled with a slight delay relative to the discharge moments of the integrators 6 and 7. This eliminates the voltage dips that occur at the output of block 1, and the output of the device is a piecewise constant voltage corresponding to the derivative.

Claims (1)

USSR copyright certificate "> 758184, cl. G 06 G 7/18, 1978. (54.) A DEVICE FOR DIFFERENTIATING AN OGF, comprising a sampling-storage unit, the input and output of which is connected to the corresponding inputs of the first subtraction unit, a first integrator and a pulse generator, characterized in that, in order to increase noise immunity, the device contains a second integrator, a second subtraction unit, a pulse distributor and a smoothing filter through which the output of the first subtraction block is connected to the output of the device, while the output of the pulse generator is connected to the input of the pulse distributor ow, the information inputs of the first and second integrators are connected to the input of the device, and their zeroing inputs are respectively connected to the first and second outputs of the pulse distributor, the outputs of the integrators are connected to the inputs of the second subtraction unit, the output of which is connected to the information input of the sample-storage unit, the control input of which connected to the third output of the pulse distributor.